Today, a circuit board normally consists of a number of especially rigid layers of fibreglass reinforced cured epoxy resin boards which are copper clad on one or both sides or provided with conductor tracks. The circuit board is fitted with semiconductor components, with connecting elements, with elements for heat dissipation or the like. In this sense, the term “assembling” must be interpreted widely in the text which follows.
It is known to fit circuit boards with discrete semiconductor components which have a housing with contact pins. In the housing, at least one semiconductor die is located which is electrically connected to the contact pins, for example bonded.
During the ever-increasing miniaturisation in the design of circuit boards, it has also become known to apply a semiconductor die without housing directly to the circuit board in one application step. Such a semiconductor die is called a “semiconductor die”. In this direct assembly, the application step is mostly followed by a bonding step in which the semiconductor die is electrically contact-connected to the circuit board.
In the known method (U.S. Pat. No. 6,809,935 B1, FIG. 1), a semiconductor die is attached directly to the metallic baseplate which provides a flat heat sink for the circuit board. This ensures good dissipation of the heat generated by the semiconductor component. It is problematic, however, that the heat expansion coefficients of the baseplate and of the semiconductor die are different from one another which must be compensated by an adhesive layer arranged between baseplate and semiconductor die. In the long term, this leads to an unwanted temperature-related mechanical loading on the semiconductor die.